Static const TickType_t timeOut = portMAX_DELAY If (inlen modbusTcp->port.buf, MAX_MODBUS_TCP_FRAME_LEN, 0)isOppened = 0 ДEBUG_LOG(('Socket %d closed! ', params->socketNum)) I just emulate response for 20 holding register request (so here no modbus stack processing at all) Params->modbusTcp->event.post( EV_FRAME_RECEIVED ) Inlen = FreeRTOS_recv(socket, params->modbusTcp->port.buf, MAX_MODBUS_TCP_FRAME_LEN, 0) Params->modbusTcp->port.addTcpSocket(socket) Params->modbusTcp->port.tcpInit(MB_TCP_PORT) XQueueReceive(params->queue, &socket, portMAX_DELAY) ДЇreeRTOS_setsockopt( socket, 0, FREERTOS_SO_RCVTIMEO, &xReceiveTimeOut,ДЇreeRTOS_setsockopt( socket, 0, FREERTOS_SO_SNDTIMEO, &xSendTimeOut,ДEBUG_LOG(('Socket %d oppened! ', params->socketNum)) Static const TickType_t xSendTimeOut = pdMS_TO_TICKS( 5000 ) ДEBUG_LOG(('socket %d task stated ', params->socketNum)) Static const TickType_t xReceiveTimeOut = pdMS_TO_TICKS( 5000 )

* They just blocks when sokets are closed */ДЇor (u32 i = 0 i port.buf = socketTaskParams.buf ДEBUG_LOG(('creating socket task %d ', socketTaskParams.socketNum )) Д¬onfigMINIMAL_STACK_SIZE*10, &socketTaskParams, 2, &socketTaskHandle) * task for all sockets are created and never deleted. MbPollActivate = xSemaphoreCreateBinary() Void * eMBRegCoilsCB, void * eMBRegDiscreteCB) Static void createSockets (void * eMBRegInputCB, void * eMBRegHoldingCB, There is nothing I can do with it.Д«y the way. Within a TCP/Modbus connection, is it really necessary to poll so often? If delay is bigger than 50 ms it write delay value to text file (delay value in seconds). So I wrote simple python script that sends modbus request to my modbus slave and measures delay between request and response. There is about one 100 ms time-out in about 100k-200k requests/response pairs. There is difficult to see time-outs in pcap because there is too much request. Yanvasilij wrote on Friday, February 03, 2017: UsChecksum = FreeRTOS_htons( usChecksum ) A value of zero would mean that the checksum is not used. * In case of UDP, a calculated checksum of 0x0000 is transmittedДЄs 0xffff.

#endif /* ipconfigHAS_DEBUG_PRINTF != 0 */ (for debugging or for higher level protocols that donвЂ™t care)Д«ut if IвЂ™m not mistaken, for other protocols this should not apply and thus: if( ( usChecksum = 0u ) & ( ucProtocol = ( uint8_t ) ipPROTOCOL_UDP ) )ДЇreeRTOS_debug_printf( ( 'usGenerateProtocolChecksum: crc swap: %04X ', pcType, usChecksum ) ) An all zero transmittedД¬hecksum value means that the transmitter generated no checksum If the computed checksum is zero, it is transmitted as all ones (theД®quivalent in oneвЂ™s complement arithmetic). The reason that 0x0 was transmitted as 0xffff is because of the UDP rule, see rfc768 : Heinbali01 wrote on Sunday, January 29, 2017:

Modbus poll checksum error